Preliminary Study Of Bone Marrow Mesenchymal Stromal Cell In Patients With Chronic Myelomonocytic Leukemia

Background: Chronic myelomonocytic leukemia(CMML)is a cancer that starts in blood-forming cells from the bone marrow and invades into blood.CMML showed both characteristics of myelodysplastic syndromes(MDS)and myeloproliferative neoplasm(MPN).Although the cause of CMML remains unclear,emerging evidences indicated that dysfunction of the bone marrow microenvironment was involved in the formation and progression of CMML.Recent studies had revealed that dysfunctional bone marrow mesenchymal stromal cells(BM-MSC)impaired the stability of hematopoietic stem cells(HSC)and gave rise to phenotypes of ineffective hematopoiesis and neoplasms in both animal models and MDS patients samples.According to the 2016 revision to the World Health Organization classification of myeloid neoplasms and acute leukemia,dysfunction of bone marrow microenvironment was taken as one of the most important pathogenesis of multiple myeloid neoplasms,it will be of great clinical and fundamental value exploring microenvironmental details of CMML.Objective: To assess the proportion profiles of bone marrow stromal cells in CMML patients;to investigate the immunological and functional phenotypes of BM-MSC in CMML patients;to evaluate relationship between colony forming unit-fibroblast(CFU-F)counts and multiple clinic characteristics in CMML patients;to investigate transcriptional characteristics in CMML.Methods: Proportion profiles of bone marrow stromal cells were detected using flow cytometry;CFU-F Assays and differentiation Assays were carried to determine potentials of fibroblast forming and osteoblast differentiation;q PCR Assays were performed to determine the expression of transcripton related to osteoblast differentiation;correlation analysis between CFU-F counts and clinic characteristics was performed;RNA sequencing(RNA-seq)was performed and analyzed in order to investigate the transcriptional characteristics;?-galactosidase and Annexin V/PI assays were performed to determine the senescence.Results: Proportions of primary BM-MSC,osteoblasts significantly decreased,while the percentage of endothelial cells and non-hematopoietic stromal cells significantly increased in CMML;multiple dysfunction of BM-MSC were seen concerning fibroblast forming and osteoblast differentiation;the counts of CFU-F was correlated to clinic characteristics in CMML patients;primary BM-MSC from CMML patients exhibited a remarkable enrichment in senescence.Conclusion: Disorders of bone marrow stromal cells exist in CMML patients samples;functional impairment was seen in CMML BM-MSC;dysfunction of BM-MSC in CMML was correlated to multiple clinic significance,implying that CFU-F counts might have an prognostic impact on CMML patients;BM-MSC from CMML patients exhibited significant senescence in both transcriptional and functional levels.